There are many kinds of conventional massage chairs. For enhancing comfortable feeling, all of the conventional massage chairs are designed with lying function. The user may adjust the slant angle depending on his need so as to allow his body in a lying status. Partly because of the lying, the body can relax, and partly because of the body weight on the massage chair where the body back is against, the massage force is increased.
Although the conventional massage chairs in the market or prior art all have the design of lying angle adjustment, but they all use the backrest to form a slant angle. The seat is fixed to the base, and forms a rigid body. In other words, the seat won't follow the backrest to incline. For such kind of design, the user's hips won't move. Only the body back lies. It is unable to form the best and the most comfortable rest status for the user. Besides, the backrest of the massage chair depends on single shaft to rotate. It requires gear transmission. The mechanical design of gear transmission is complicate and higher cost. It increases the difficulty and the cost of future service.